x := yes
y := x and (1 < 2)
z := nil

if x and y and z == nil
    say "And pass"
else
    fail "'and' failed"

if 1 < 0 or 2 < 1 or 3 > 1
    say "Or pass"
else
    fail "'or' failed"

if no xor yes xor no
    say "Xor pass"
else
    fail "'xor' failed"